I only leave redirects when I feel that the thread might be of interest to the people who follow that board. Otherwise, almost everyone just clicks Show new replies to your posts anyway, so I'm not worried about them wondering where it went.
Since I use "show new replies", I wish there was a way to remove any and all "moved" topics so I don't have to click each one of them to mark it read.
Actually, a "mark as read or unread" button on each topic would be cool...